Why the use of pop-up ads on proxy sites may be good for proxy users, if it ensures the continued availability
of proxy sites -- and why, counterintuitively, more intrusive ads may be better for users in the long run,
for the same reason.

A simple experiment shows that the popular anti-censorship program
UltraSurf would be easy for countries to block with a little effort.
But experience also shows that most countries aren't trying very hard to block anti-censorship tools, so UltraSurf
will continue to benefit many users. We should just be aware that such programs don't have any magic powers
that prevent them from being blocked.

Websense, a US-based Internet-censoring software maker, claims not to sell to foreign governments that are censoring Internet access for all of their citizens.
But the OpenNet Initiative reports that national ISPs in Yemen have been using Websense to filter Internet access for at least the past four years. Will Websense revoke their license as a result?